DuckDB v1.5 spatial/GIS analytics with 155+ ST_* functions. Use this skill for DuckDB, spatial queries, GeoParquet, geometry data, or geospatial analytics. Workflow: Discovery → Understanding → Analysis (Phase 1: glob/DESCRIBE/ST_Read_Meta, Phase 2: SUMMARIZE/parquet_metadata/CRS detection, Phase 3: targeted queries). Query profiling with EXPLAIN ANALYZE for troubleshooting. Spatial: CRS/EPSG transforms, automatic R-Tree indexes, distance/area calculations, spatial joins, H3/A5/S2 indexing, QUADBIN tiling, geometry shredding (3x compression), core GEOMETRY type (no extension), GeoParquet (v1/v2/BOTH), GDAL formats (Shapefile, GeoJSON, GeoPackage, FlatGeobuf, OSM). Data sources: Overture Maps (6 themes), DuckLake lakehouse, Apache Iceberg (REST catalogs, time travel), BigQuery connector, raster (RaQuet, raquet-io CLI), VARIANT type. Also: BM25/FTS, HNSW vector search, friendly SQL, Python API, v1.5 breaking changes, common pitfalls.
2026-03-19